Polymorphism in introns 5 and 6 of the ACTA1 gene in various Polish horse breeds

Authors: DANIEL POLASIK, RYSZARD PIKULA

Abstract: The aim of this study was to find polymorphisms in the actin alpha 1 gene (ACTA1) in horses belonging to different breeds and utility types and to compare them. The genomic region of the actin alpha 1 gene was positively selected in purebred horses. By sequencing part of the ACTA1 gene, 2 polymorphic sites located in intron 5 (G > T) and intron 6 (G > C) were found. The polymerase chain reaction-restriction fragment length polymorphism and the amplification created restriction site-polymerase chain reaction methods were applied to screen these polymorphisms. An analysis of the genotype and allele frequencies showed differences depending on the breed and utility type. Other genetic parameters such as heterozygosity and gene diversity revealed similar relationships. For some breeds, deviation from genetic equilibrium was observed. Haplotype analysis showed that 2 of 4 haplotypes were common to all breeds, 1 haplotype was absent in primitive horses, and 1 haplotype was observed only in Purebred Arabian horses and Malopolski horses (a breed that is known to have Arabian ancestors). It seems reasonable to conclude that distribution of the haplotypes of the ACTA1 gene among the populations studied may be the result of long-standing selection for physical performance.

Keywords: Horse, utility type, single nucleotide polymorphism, ACTA1 gene

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